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we present a new stabilised and efficient high-order nodal spectral element method based on the mixed eulerian lagrangian (mel) method for general-purpose simulation of fully nonlinear water waves and wave-body interactions. in this mel formulation a standard laplace formulation is used to handle arbitrary body shapes ... | a stabilised nodal spectral element method for fully nonlinear water waves, part 2: wave-body interaction |
we study the natural transverse vibrations of a constant-length part of a rectilinear thin rod moving along a neutral line in unstrained state. the displacement occurs between two fixed coaxial rod guides (clamps) and the distance between them is equal to the length of the vibration part of the rod. moreover, it is ass... | transverse vibration spectrum of a part of a moving rod under a longitudinal load |
in this work, a new unconditionally stable finite-difference time-domain (fdtd) method with the split-field perfectly matched layer (pml) is proposed for the analysis of time reversal (tr) waves. the proposed method is very suitable for multiscale problems involving microstructures. the spatial and temporal derivatives... | newmark-beta-fdtd method for super-resolution analysis of time reversal waves |
we present a numerical method for modeling the mechanical effects of nonlinearly-compliant joints in elasto-plastic media. the method uses a series of strain-rate and stress update algorithms to determine joint closure, slip, and solid stress within computational cells containing multiple "embedded" joints. this work f... | an algorithm for continuum modeling of rocks with multiple embedded nonlinearly-compliant joints |
the acoustic wave equation describes wave propagation directly from basic physical laws, even in heterogeneous acoustic media. when numerically simulating waves with the wave equation, contrasts in the medium parameters automatically generate all scattering effects. for some applications - such as propagation analysis ... | a non-reflecting wave equation through directional wave-field suppression and its finite difference implementation |
a normal metal-superconductor hybrid single-electron trap with tunable barrier is utilized as a tool for spectrum analysis at the extremely low signal levels, using only well filtered cryogenic microwave background as a photon source in the frequency range from about 50 to 210 ghz. we probe millimeter wave propagation ... | characterizing superconducting filters using residual microwave background |
in this paper, two fully-adaptive explicit time-marching procedures are discussed for the time-domain solution of wave propagation in elastic media. in these procedures, the time integration parameters of the methods are adaptively locally evaluated, following the properties of the discretized model and the values of t... | elastodynamic wave propagation modelling in geological structures considering fully-adaptive explicit time-marching procedures |
in this paper, systematic wave-equation finite difference time domain (we-fdtd) formulations are presented for modeling electromagnetic wave-propagation in linear and nonlinear dispersive materials. in the proposed formulations, the complex conjugate pole residue (ccpr) pairs model is adopted in deriving a unified disp... | systematic wave-equation finite difference time domain formulations for modeling electromagnetic wave-propagation in general linear and nonlinear dispersive materials |
a new application for reverberation tanks, used to measure the sound energy of impulsive sound sources, is proposed. according to the law of conservation of energy, the impulsive sound energy obtained by sound intensity integration in the time domain is the same as the sound energy density spectrum obtained by integrat... | a new application for reverberation tanks: measurement of underwater impulsive sound characteristics |
acousto-optic tunable filters (aotf) are used in the development of hyperspectral imagers from the ultra violet (uv) to the long wave infrared (lwir). they have the advantage to be an all-solid-state and robust device with no-moving parts that can fast tune their filtered frequency carrier. such a device is developed b... | acousto-optic interaction model with mercury halides (hg2cl2 and hg2br2) as aotf cristals |
the mass-in-mass (mim) lattice consists of an infinite chain of identical beads that are both nonlinearly coupled to their nearest neighbors and linearly coupled to a distinct resonator particle; it serves as a prototypical model of wave propagation in granular crystals and metamaterials. we study traveling waves in an... | small mass nanopteron traveling waves in mass-in-mass lattices with cubic fput potential |
the weak-field approximation, implying a linear relationship between stokes-v /i and the longitudinal magnetic field [b∥], often suffers from saturation observed in strong magnetic-field regions such as sunspot umbrae. in this work, we seek to improve the magnetic-field observations carried out by the solar magnetic fi... | improvements of the longitudinal magnetic field measurement from the solar magnetic field telescope at the huairou solar observing station |
modern-day civil, mechanical, and aeronautical structures are transitioning towards a continuous, online, and automated maintenance paradigm in order to ensure increased safety and reliability. the field of structural health monitoring (shm) is playing a key role in this respect and active sensing acousto-ultrasound gu... | time-varying identification of guided wave propagation under varying temperature via non-stationary time series models |
a lead bismuth eutectic (lbe) spallation target will be installed in the target test facility (tef-t) in the japan proton accelerator research complex (j-parc). the spallation target vessel filled with lbe is made of type 316l stainless steel. however, various damages, such as erosion/corrosion damage and liquid metal ... | effects of grain size on ultrasonic attenuation in type 316l stainless steel |
the containment liner plate (clp) in a nuclear power plant is the most critical part of the structure of a power plant, as it prevents the radioactive contamination of the surrounding area. this paper presents feasibility of structural health monitoring (shm) and an elastic wave tomography method based on ultrasonic gu... | an investigation on a quantitative tomographic shm technique for a containment liner plate in a nuclear power plant with guided wave mode selection |
we report on numerical modelling of three-dimensional lattice structures designed to provide phononic bandgaps. the examined lattice structures rely on two distinct mechanisms for bandgap formation: the destructive interference of elastic waves and internal resonance. further to the effect of lattice type on the develo... | multidimensional phononic bandgaps in three-dimensional lattices for additive manufacturing |
the nonlinear solitary wave in a magnetized plasma with the combined effect of ion collision and trapped electrons distribution is investigated. using the reductive perturbation technique, the damped modified schamel-zakarov-kuznetsov nonlinear wave equation is derived and analyzed numerically. solitary wave propagatio... | nonlinear ion acoustic solitary wave in collisional pair ion plasma with trapped electrons |
measuring the state of polarization of light is critical because it contains information about its source, including radiation, reflection, and any other interactions with matter. however, the traditional method to operate polarimetry relies on knowing the direction of wave propagation. otherwise, one measures only the... | single-shot omnidirectional stokes polarimetry using radially polarized light |
for the fatigue crack embedded in metallic components, the non-collinear transverse wave mixing technique is applied to detect them and image the fatigue damage around crack. when two non-collinear transverse waves with same frequency meet in components, a resonance longitudinal wave can be generated if the resonance c... | fatigue crack detection and fatigue damage imaging using the non-collinear transverse wave mixing technique |
this work describes the development and optimization of an implementation of an isotropic elastodynamic finite integration technique (efit) code for parallelized computation on intel knights landing (knl) hardware. efit is a numerical approach resulting in standard staggered-grid finite difference equations for the ela... | optimization of elastodynamic finite integration technique on intel xeon phi knights landing processors |
in this study, we analyzed the performance of a preliminary three-dimensional (3d) velocity model of the eastern caucasus covering most of the azerbaijan. the model was developed in support to long-period ground motion simulations and seismic hazard assessment from regional earthquakes in azerbaijan. the model's perfor... | ground motion modeling in the eastern caucasus |
condition assessment of pipeline networks is critical to ensure operation safety considering that the network around the us is aging. this work aims at combining guided ultrasonic waves and advanced tomographic algorithms to locate corrosion-induced defects in both inner and outer surfaces of steel pipes. particularly,... | a helical-based ultrasonic imaging algorithm for structural health monitoring of cylindrical structures |
the linear and weakly nonlinear dust-ion-acoustic wave propagation obliquely to an external magnetic field is studied in a magnetized dusty plasma which consists of magnetized fluid ions bearing with anisotropic pressure, suprathermal electrons, and static dust grains. in the linear regime, the magnetized dusty plasma ... | chaotic dynamics of dust-ion acoustic wave in magnetized dusty plasma with anisotropic ion pressure |
sunspots are the most striking and easily observed magnetic structures of the sun, and statistical analysis of solar historical data could reveal a wealth of information on the long-term variation of solar activity cycle. the hand-drawn sunspot records of yunnan observatories, chinese academy of sciences have been accu... | chinese sunspot drawings and their digitization - (ii) accuracy analysis for digitized sunspot hand-drawing records of yunnan observatories |
flows of fluids made of complex organic molecules exhibit unconventional fluid dynamic behavior in the vapor phase if their thermodynamic state is close to that of the vapor-liquid critical point. if the molecule is sufficiently complex, this thermodynamic domain is characterized by negative values of the fundamental d... | nonlinear wave propagation in dense vapor of bethe-zel'dovich-thompson fluids subjected to temperature gradients |
a recently proposed photonic bandgap material, named "photonic amorphous diamond" (pad), was fabricated in a terahertz regime, and its terahertz-wave propagation properties were investigated. the pad structure was fabricated from acrylic resin mixed with alumina powder, using laser lithographic, micro-additive manufact... | fabrication of photonic amorphous diamonds for terahertz-wave applications |
the conventional finite-difference time-domain (fdtd) method for elastic waves suffers from the staircasing error when applied to model a curved free surface because of its structured grid. in this work, an improved, stable and accurate 3-d fdtd method for elastic wave modelling on a curved free surface is developed ba... | a 3-d enlarged cell technique (ect) for elastic wave modelling of a curved free surface |
this paper reviews the literature on the response of polymers to high strain rate deformation. the main focus is on the experimental techniques used to characterize this response. the paper includes a small number of examples as well as references to experimental data over a wide range of rates, which illustrate the ke... | high strain rate characterization of polymers |
we present techniques and algorithms for automatic processing and interpretation of data of ionospheric backscatter sounding (bs) using a continuous chirp signal. experimental ionograms are processed based on data filtration with further compression using the cellular automaton method. interpretation of signals in a ba... | real-time techniques for interpretation of ionospheric backscatter sounding data |
the performance of global navigation satellite system (gnss) receivers is limited by the ionospheric scintillation effects that cause signal degradation due to refraction, reflection and scattering of the signals. hence, there is a need to develop an ionospheric scintillation detection technique for robust gnss receive... | robust detection of ionospheric scintillations using mf-dfa technique |
temporal changes in seismic anisotropy can be interpreted as variations in the orientation of cracks in seismogenic zones, and thus as variations in the stress field. such temporal changes have been observed in seismogenic zones before and after earthquakes, although they are still not well understood. in this study, w... | influence of seismic anisotropy on the cross correlation tensor: numerical investigations |
this paper reviews recent progress in the measurement and modelling of stochastic electromagnetic fields, focusing on propagation approaches based on wigner functions and the method of moments technique. the respective propagation methods are exemplified by application to measurements of electromagnetic emissions from ... | stochastic electromagnetic field propagation— measurement and modelling |
recently, there has been an increased interest in exploring periodic structures having higher symmetry properties, primarily based on metallic realization. the design of dielectric glide-symmetric structures has many challenges, and this paper presents a systematic analysis approach based on floquet mode decomposition ... | modeling of glide-symmetric dielectric structures |
the analysis of high-frequency wave propagation in waveguides of arbitrarily shaped cross-sections requires specific numerical methods. a rather common technique consists in discretizing the cross-section with finite elements while describing analytically the axis direction of the waveguide. this technique enables to a... | free and forced response of three-dimensional waveguides with rotationally symmetric cross-sections |
numerical simulation of nonlinear elastic wave propagation in solids with cracks is indispensable for decoding the complicated mechanisms associated with the nonlinear ultrasonic techniques in non-destructive testing (ndt). here, we introduce a two-dimensional implementation of the combined finite-discrete element meth... | simulation of crack induced nonlinear elasticity using the combined finite-discrete element method |
secondary microseismic sources emit seismic waves over long time spans. reoccurring signals with similar slowness and frequency therefore arrive at seismic arrays. blind source separation techniques can be used to identify and isolate such reoccurring signals from other signals and from diffuse seismic noise. along the... | blind source separation of temporally independent microseisms |
compressional and shear velocities were measured at room temperature and ambient pressure on cylindrical samples. the p-wave and s-wave velocities have been measured at ultrasonic frequencies of 63 khz and 33 khz, respectively. compressional and shear waves have different behaviour in rocks depending on difference in p... | effect of fluid saturation on acoustic wave velocity for sandstone reservoirs |
reverse time migration (rtm) is an indispensable but computationally intensive seismic exploration technique. graphics processing units (gpus) by nvidia® offer the option for parallel computations and speed improvements in such high-density processes. with increasing seismic imaging space, the problems associated with ... | an efficient scheme for multi-gpu tti reverse time migration |
we propose a three-dimensional non-hydrostatic shock-capturing numerical model for the simulation of wave propagation, transformation and breaking, which is based on an original integral formulation of the contravariant navier-stokes equations, devoid of christoffel symbols, in general time-dependent curvilinear coordi... | numerical integration of the contravariant integral form of the navier-stokes equations in time-dependent curvilinear coordinate systems for three-dimensional free surface flows |
this paper details the extension of a metric-based anisotropic mesh adaptation strategy to the boundary element method for problems of 3d acoustic wave propagation. traditional mesh adaptation strategies for boundary element methods rely on galerkin discretizations of the boundary integral equations, and the developmen... | metric-based anisotropic mesh adaptation for 3d acoustic boundary element methods |
most of modeling and simulation of high temperature superconducting (hts) cables are inadequate for high frequency analysis since focus of the simulation's frequency is fundamental frequency of the power grid, which does not reflect transient characteristic. however, high frequency analysis is essential process to rese... | modeling and simulation of hts cables for scattering parameter analysis |
dust explosion hazards in areas where coal and other flammable materials are found have caused unnecessary loss of life and halted business operations in some instances. the elimination of secondary dust explosion hazards, i.e., reducing dust dispersion, can be characterized in shock tubes to understand shock-dust inte... | a new facility for studying shock-wave passage over dust layers |
in the present work, dynamic response of cracked timoshenko beam with functionally graded material properties are obtained by a numerical technique using ritz approximation. in order to verify the applicability and performance of the formulation, comparisons of the present numerical method with three-dimensional fem mo... | crack modelling and detection in timoshenko fgm beam under transverse vibration using frequency contour and response surface model with ga |
we employ noncontact optical techniques to generate and measure stress waves in uncompressed, one-dimensional microscopic granular chains, and support our experiments with discrete numerical simulations. we show that the wave propagation through dry particles (150 μm radius) is highly nonlinear and it is significantly ... | wave propagation in one-dimensional microscopic granular chains |
additive manufacturing (am) is viewed as a revolutionary technique as it offers numerous appealing capabilities such as complex geometries, functionally graded properties, build-upon-demand, repairs, etc. however, in order to attain the full potential of am, nondestructive testing for quality assurance of am parts is e... | influence of surface roughness from additive manufacturing on laser ultrasonics measurements |
the soil-structure interaction (ssi) is generally neglected for seismic design of ordinary buildings. a modeling technique is proposed to facilitate the integration of ssi in building design, considering rocking effects and the shallow foundation deformability. the proposed technique is suitable when the soil can be co... | soil-structure interaction analysis using a 1dt-3c wave propagation model |
aims: we aim to study the dynamical evolution of transequatorial loops (tels) using imaging techniques and spectroscopy.methods: we used the images recorded by the atmospheric imaging assembly and the helioseismic magnetic imager on board the solar dynamics observatory together with spectroscopic observations taken fro... | formation and dynamics of transequatorial loops |
numerical mode matching (nmm) methods are widely used for analyzing wave propagation and scattering in structures that are piece-wise uniform along one spatial direction. for open structures that are unbounded in transverse directions (perpendicular to the uniform direction), the nmm methods use the perfectly matched l... | a numerical mode matching method for wave scattering in a layered medium with a stratified inhomogeneity |
frequency estimation is a fundamental problem in signal processing, with applications in radar imaging, underwater acoustics, seismic imaging, and spectroscopy. the goal is to estimate the frequency of each component in a multisinusoidal signal from a finite number of noisy samples. a recent machine-learning approach u... | data-driven estimation of sinusoid frequencies |
we begin here a series of papers examining the chromospheric and coronal properties of solar active regions. this first paper describes an extensive data set of images from the atmospheric imaging assembly on the solar dynamics observatory curated for large-sample analysis of this topic. based on (and constructed to co... | properties of flare-imminent versus flare-quiet active regions from the chromosphere through the corona. i. introduction of the aia active region patches (aarps) |
aims: this study investigates and compares the physical properties, such as intensity and area, of coronal bright points (cbps) inside and outside of coronal holes (chs) using the atacama large millimeter/submillimeter array (alma) and solar dynamics observatory (sdo) observations.methods: the cbps were analysed using ... | differences in physical properties of coronal bright points and their alma counterparts within and outside coronal holes |
a two-dimensional problem of shear horizontal (sh) waves scattering by a finite width planar elastic (piezoelectric) inclusion partially debonded from its surrounding elastic matrix is investigated using the effective boundary conditions and singular integral equations technique. the case of large rigidity inclusions w... | two-dimensional shear waves scattering by a large rigidity strip with interface crack |
lateral velocity variations and low velocity near-surface layers can produce strong scattered and guided waves which interfere with reflections and lead to severe imaging problems in seismic exploration. in order to investigate these specific problems by laboratory seismic modelling, a simple 2d ultrasonic model facili... | the development and testing of a 2d laboratory seismic modelling system for heterogeneous structure investigations |
carbon fiber reinforced composites are increasingly used in structural parts in the aeronautics industry, as they allow to reduce the weight of aircrafts while maintaining high mechanical performances. however, such structures can be complicated to inspect due to their complex geometries and complex composite propertie... | simulation of ultrasonic inspection of curved composites using a hybrid semi-analytical/numerical code |
from the applications perspective the electron density is the major determining parameter of the ionosphere due to its strong impact on the radio signal propagation. as the most ionized ionospheric region, the f2 layer has the most pronounced effect on transionospheric radio wave propagation. the maximum electron densi... | comparing different assimilation techniques for the ionospheric f2 layer reconstruction |
in concrete structures, moisture is often a major cause of chemically related degradations such as alkaline-silica reaction. to develop ultrasonic nondestructive evaluation techniques for monitoring such chemical degradations, it is necessary to understand how moisture affects the propagation of ultrasound in concrete.... | effects of moisture on ultrasound propagation in cement mortar |
bender elements are shear wave transducers, used for the computation of small strain shear moduli of geomaterials. however, the distortion of the output signal caused by residual compression waves may lead to important errors in the shear modulus estimates. we present a novel procedure for the optimisation of the locat... | optimisation of receiver's location in bender element experiments using computational wave filtration |
the consideration of highly irregular topography or heterogeneities and singularities in the domain are necessary for solving a wide variety of seismic problems, e. g. earthquake site studies. therefore, the use of a meshless method (mm) with the possibility of employing an irregular grid point distribution can be of i... | wave propagation in soils problems using the generalized finite difference method |
electron source coherence has a very important influence on the imaging capabilities of modern electron microscopes. however, conventional electron source models that are based on geometrical electron optics implicitly assume that the emission from the source surface is fully incoherent, which can complicate the treatm... | wave-mechanical electron-optical modeling of field-emission electron sources |
this paper presents a system with location functionalities for the inventory of traffic signs based on passive rfid technology. the proposed system simplifies the current video-based techniques, whose requirements regarding visibility are difficult to meet in some scenarios, such as dense urban areas. in addition, the ... | passive rfid-based inventory of traffic signs on roads and urban environments |
we consider the problem of localizing small material defects in rectangular bounded domains. the scalar acoustic equation is used to model wave propagation in this context. our data is the scattered field collected at one or more receivers and due to impulsive excitations at one or more source positions. to localize th... | signal-to-noise ratio analysis for time-reversal based imaging techniques in bounded domains |
this paper studies the new closed form solutions to (2+1)-dimensional bogoyavlenskii system that describes interaction of a riemann wave propagation. the extended fan sub-equation technique is used to investigate some new traveling wave solutions to the higher-dimensional coupled model. the obtained closed form solutio... | on new closed form solutions: the (2+1)-dimensional bogoyavlenskii system |
the intensity of damage production during shock wave propagation in polycrystalline metallic systems is mostly dependent on the shock-defect interactions. traditionally, different coincidence site lattice (csl) grain boundaries (gbs) are introduced in the polycrystalline structure through various processing techniques ... | effect of variation in inclination angle of ʃ5 tilt grain boundary on the shock response of ni bicrystals |
magnetic resonance-guided high intensity focused ultrasound (mr-hifu) has been clinically shown to be effective for palliative pain management in patients suffering from skeletal metastasis. the underlying mechanism is supposed to be periosteal denervation caused by ablative temperatures reached through ultrasound heat... | modelling the temperature evolution of bone under high intensity focused ultrasound |
this study explores the interplay between wave propagation and damage in brittle materials. the damage models, based on micro-mechanical fracture dynamics, capture any possible unstable growth of micro-cracks, introducing a macroscopic loss of stability. after stating the non-dimensional mathematical problem describing... | micro-mechanical fracture dynamics and damage modelling in brittle materials |
co2 injection in saline aquifers is one solution to avoid the emission of this greenhouse gas to the atmosphere. this process induces a pore-pressure build-up around the borehole that generates tensile and shear micro-earthquakes which emit p and s waves if given pressure thresholds are exceeded. here, we develop a sim... | modeling techniques to study co2-injection induced micro-seismicity |
when a seismic wave propagates in a fluid-saturated porous medium, a relative movement forms between the solid and the fluid and induces an electric current due to the electronic double layer. as a result, two kinds of seismoelectric coupling responses are generated in this procedure: the localized electric/magnetic fi... | experimental studies on the mechanism of seismoelectric logging while drilling with multipole source |
summarynonparametric techniques for estimation of wave dispersion in buildings by seismic interferometry are applied to a simple model of a soil–structure interaction (ssi) system with coupled horizontal and rocking response. the system consists of a viscously damped shear beam, representing a building, on a rigid foun... | wave dispersion in high‑rise buildings due to soil–structure interaction |
backward cylindrical leaky waves radiating in the direction of their central axis represent an efficient solution for generating nondiffracting bessel-like beams. the structures proposed so far to support such waves, constituted by concentric metal rings printed on a grounded dielectric slab, ensure the formation of no... | spiral antennas for the generation of bessel beams with tunable nondiffractive range |
a multiple monopole method based on the generalized multipole technique is presented for the calculation of band structures of two-dimensional mixed solid/fluid phononic crystals. in this method, the fields are expanded by using the fundamental solutions with multiple origins. besides the sources used to expand the wav... | application of the generalized multipole technique in band structure calculation of two-dimensional solid/fluid phononic crystals |
a novel tip-enhanced raman spectroscopy setup with longitudinal field excitation generated by a plasmonic lens is investigated. a symmetry-breaking structure plasmonic lens that is expected to realize a strong longitudinal electric field focus has been designed to generate suitable excitation for enhancement in a tip a... | plasmonic lens focused longitudinal field excitation for tip-enhanced raman spectroscopy |
a signal processing technique is presented in this paper to normalize and separate the source of non-linear acoustic emission (ae) signals of a multi-cylinder diesel engine for condition monitoring applications and fault detection. the normalization technique presented in the paper overcomes the long-existing non-linea... | normalization and source separation of acoustic emission signals for condition monitoring and fault detection of multi-cylinder diesel engines |
comb-drive transducers are made of interdigitized fingers formed by the stationary part known as stator and the moving part known as rotor, and based on the transduction principle of capacitance change. they can be designed as area-change or gap-change mechanism to convert the mechanical signal at in-plane direction in... | the design, characterization, and comparison of mems comb-drive acoustic emission transducers with the principles of area-change and gap-change |
it has long been recognized that woodpecker is an excellent anti-shock organism, as its head and brain can bear high deceleration up to 1500 g under fast pecking. to investigate the mechanism of brain protection of woodpecker, we built a finite element model of a whole woodpecker using computed topography scanning tech... | how woodpecker avoids brain injury? |
in this article, the abundant wave solutions of boussinesq equations are obtained, which are very important to investigate the waves propagation of shallow water. firstly, we establish the time-fractional form of (1 + 1) dimensional boussinesq equations to describe the shallow water waves more accurately. furthermore, ... | variant wave propagation patterns by coupled bossinesq equations |
the recent achievements in the accelerometer-based seismocardiography field indicate a strong potential for this technique to address a wide variety of clinical needs. recordings from different locations on the chest can give a more comprehensive observation and interpretation of wave propagation phenomena than a singl... | airborne ultrasound surface motion camera: application to seismocardiography |
photoacoustic imaging has shown great promise for medical imaging, where optical energy absorption by blood haemoglobin is used as the contrast mechanism. a numerical method was developed for the in-silico assessment of the photoacoustic image reconstruction of the brain. image segmentation techniques were used to prep... | a numerical model for the study of photoacoustic imaging of brain tumours |
context. previous helioseismology of sunspots has been sensitive to both the structural and magnetic aspects of sunspot structure.aims: we aim to develop a technique that is insensitive to the magnetic component so the two aspects can be more readily separated.methods: we study waves reflected almost vertically from th... | probing sunspots with two-skip time-distance helioseismology |
at iowa state university's center for nondestructive evaluation (isu cnde), the use of models to simulate ultrasonic inspections has played a key role in r&d efforts for over 30 years. to this end a series of wave propagation models, flaw response models, and microstructural backscatter models have been developed t... | techniques and software tools for estimating ultrasonic signal-to-noise ratios |
this paper presents the modeling technique, working mechanism and design guidelines for acoustic multi-stopband metamaterial plates for broadband elastic wave absorption and vibration suppression. the metamaterial plate is designed by integrating two-dof (degree of freedom) mass-spring subsystems with an isotropic plat... | design of multi-stopband metamaterial plates for absorption of broadband elastic waves and vibration |
the trefftz discontinuous galerkin (tdg) method is a technique for approximating the helmholtz equation (or other linear wave equations) using piecewise defined local solutions of the equation to approximate the global solution. when coefficients in the equation (for example, the refractive index) are piecewise constan... | numerical simulation of wave propagation in inhomogeneous media using generalized plane waves |
radio map prediction (rmp), aiming at estimating coverage of radio wave, has been widely recognized as an enabling technology for improving radio spectrum efficiency. however, fast and reliable radio map prediction can be very challenging due to the complicated interaction between radio waves and the environment. in th... | radionet: transformer based radio map prediction model for dense urban environments |
pressure vessels usually operate under extremes of high/low temperatures and high pressures. defect, such as crack and corrosion, can result in leakage or rupture failures, even catastrophic incidents. guided wave-based structural health monitoring (shm) technology is one of the most prominent options in non-destructiv... | propagation of guided waves in pressure vessel |
the frequency dependence of scattering parameters of interdigital surface acoustic wave transducers placed on ferroelectric barium titanate (batio3) epitaxial film in c-phase coated over magnesium oxide has been studied using the finite-element method (fem) approach along with the perfectly matched layer (pml) techniqu... | finite-element analysis of scattering parameters of surface acoustic wave bandpass filter formed on barium titanate thin film |
probing of human lungs using pulse compression techniques in the low-frequency range of 80-1000 hz established the fact of preferential sound conduction of longitudinal rather than shear waves to the chest surface via lung parenchyma at propagation velocities from 100 to 15 m/s. probing via the mouth for the first two ... | features of sound conduction in human lungs in the 80-1000 hz and 10-19 khz frequency ranges |
a rigorous technique for the consistent calculation of the effective parameters of infinite three-dimensional metamaterial particle arrays in the realistic case of oblique wave propagation, is presented in this paper. the extracted polarizabilities of the consisting scatterer and the numerically retrieved wavenumber fo... | homogenization of 3d metamaterial particle arrays for oblique propagation via a point-dipole analysis |
we have built a fizeau fiber interferometer to investigate the internal cylindrical defects in an aluminum plate based on laser ultrasonic techniques. the ultrasound is excited in the plate by a q-switched nd:yag laser. when the ultrasonic waves interact with the internal defects, the transmitted amplitudes of longitud... | internal cylinder identification based on different transmission of longitudinal and shear ultrasonic waves |
this work presents a novel scalable and field-deployable framework for monitoring lithium-ion (li-ion) battery state of charge (soc) and state of health (soh), based on ultrasonic guided waves using low-profile built-in piezoelectric transducers. the feasibility of this technique is demonstrated through experiments usi... | battery charge and health state monitoring via ultrasonic guided-wave-based methods using built-in piezoelectric transducers |
a series of 1.27 m air gap discharge tests under negative switching impulses were carried out to characterize shock wave expansion behavior along leader channels. a high-speed schlieren system was used to identify shock wave propagation characteristics near the high-voltage electrode. according to the schlieren images,... | shock wave propagation in long laboratory sparks under negative switching impulses |
effects of seismic ground motion induced by surface geology and geometry are known to be associated with the generation of a substantial proportion of surface waves. as a consequence, surface waves significantly contribute to ground-motion variability and site amplification. there is a growing body of literature recogn... | diffracted wavefield decomposition and multidimensional site effects in the argostoli valley, greece |
acoustic emission (ae) is an in situ structural health monitoring (shm) technique, where a structure is monitored for the ultrasonic waves produced due to crack growth. a major challenge with ae when applied to aircraft, and other complex structures, is that wave propagation is significantly affected by stiffeners, hol... | advanced acoustic emission source location in aircraft structural testing |
the time reversal method has become a standard technique for the location of seismic sources. it has been used both for acoustic and elastic numerical modelling and for 2d and 3d propagation models. although there are many studies concerning its application to point sources, little so far has been done to generalise th... | time reversal seismic source imaging using peak average power ratio (papr) parameter |
parallelization techniques have been exploited most successfully by the gaming/graphics industry with the adoption of graphical processing units (gpus), possessing hundreds of processor cores. the opportunity has been recognized by the computational sciences and engineering communities, who have recently harnessed succ... | a fast mhd code for gravitationally stratified media using graphical processing units: smaug |
this paper uses curved grids in the context of a pseudo-spectral method to model 2-d sh-wave propagation in a medium with an irregular free-surface. a technique originally developed for computational fluid dynamics (cfd) is first used to generate curved grids following the irregular free-surface. then the sh-wave equat... | using pseudo-spectral method on curved grids for sh-wave modeling of irregular free-surface |
continuous high-cadence and high spatial resolution dopplergrams allow us to study subsurface dynamics that may be further extended to explore precursors of visible solar activity on the surface. since the p-mode power is absorbed in the regions of high magnetic field, the inferences in these regions are often presumed... | horizontal flows in active regions from ring-diagram and local correlation tracking methods |
advanced seismic detection technology utilising random roadway sources is advantageous method adapting to the development of dynamic intelligent technologies for the detection of hidden and disastrous geological structures. however, roadheaders generate complex signals, that are continuous and random with seismic wavel... | processing of random roadway source signals based on a cross-correlation algorithm in the deconvolution domain |
horizontal‑to‑vertical spectral ratio (hvsr) is a widely used geophysical technique in seismic microzonation studies. it is based on a specific analysis of seismic ambient noise. the method allows to obtain the frequency and amplitude of the resonance peaks of a layered earth with increasing acoustic impedance contrast... | the passive seismic technique 'hvsr' as a reconnaissance tool for mapping paleo‑soils: the case of the pilastri archaeological site, northern italy |
when a high explosive detonates, a large amount of energy is released within a short time, creating a high-temperature and high-pressure environment accompanied by a blast wave. when the blast wave interacts with field obstacles such as building structures and ground soil, it produces a reflected wave. the complexity o... | understanding the effects of blast loads on open spaces and enclosed structures in simulations and experiments |
the underwater explosion is a very complex multiphase phenomenon that poses a threat to the safety of ocean structures. numerical simulation is of great significance in understanding the underlying mechanisms of hydrodynamics and structural damages due to underwater explosions. in this study, a mesh-free method, smooth... | smoothed particle hydrodynamics simulation of underwater explosions with dynamic particle refinement |
in our work, the study of detonation wave structure was performed by visar laser interferometer for a hydrazine nitrate/h2o (hn/water) solution and pressed hn with maximum density of 1.68 g/cm3. the range of water concentration in which the hn/water solution detonated at a room temperature was found to be 25 - 36 wt.%.... | detonation properties of solution of hydrazine nitrate/water |
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